﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.Serialization;
using System.Data;
using System.Reflection;

namespace CacheAccess
{
    public class ConvertToEntity
    {
        /// <summary>
        /// DataTable与实体类互相转换
        /// </summary>
        /// <typeparam name="T">实体类</typeparam>
        public class ModelHandler<T> where T : new()
        {
            #region DataTable转换成实体类

            /// <summary>
            /// 填充对象列表：用DataSet的第一个表填充实体类
            /// </summary>
            /// <param name="ds">DataSet</param>
            /// <returns></returns>
            public List<T> FillModel(DataSet ds)
            {
                if (ds == null || ds.Tables[0] == null || ds.Tables[0].Rows.Count == 0)
                {
                    return null;
                }
                else
                {
                    return FillModel(ds.Tables[0]);
                }
            }

            /// <summary>  
            /// 填充对象列表：用DataSet的第index个表填充实体类
            /// </summary>  
            public List<T> FillModel(DataSet ds, int index)
            {
                if (ds == null || ds.Tables.Count <= index || ds.Tables[index].Rows.Count == 0)
                {
                    return null;
                }
                else
                {
                    return FillModel(ds.Tables[index]);
                }
            }

            /// <summary>  
            /// 填充对象列表：用DataTable填充实体类
            /// </summary>  
            public List<T> FillModel(DataTable dt)
            {
                if (dt == null || dt.Rows.Count == 0)
                {
                    return null;
                }
                List<T> modelList = new List<T>();
                foreach (DataRow dr in dt.Rows)
                {
                    //T model = (T)Activator.CreateInstance(typeof(T));  
                    T model = new T();
                    foreach (PropertyInfo propertyInfo in typeof(T).GetProperties())
                    {
                        model.GetType().GetProperty(propertyInfo.Name).SetValue(model, dr[propertyInfo.Name], null);
                    }
                    modelList.Add(model);
                }
                return modelList;
            }

            /// <summary>  
            /// 填充对象：用DataRow填充实体类
            /// </summary>  
            public T FillModel(DataRow dr)
            {
                if (dr == null)
                {
                    return default(T);
                }

                //T model = (T)Activator.CreateInstance(typeof(T));  
                T model = new T();
                foreach (PropertyInfo propertyInfo in typeof(T).GetProperties())
                {
                    model.GetType().GetProperty(propertyInfo.Name).SetValue(model, dr[propertyInfo.Name], null);
                }
                return model;
            }

            public List<T> FillModel(DataRow[] dr)
            {
                List<T> model = new List<T>();
                foreach (DataRow d in dr)
                {
                    model.Add(FillModel(d));
                }
                return model;
            }



            #endregion

            #region 实体类转换成DataTable

            /// <summary>
            /// 实体类转换成DataSet
            /// </summary>
            /// <param name="modelList">实体类列表</param>
            /// <returns></returns>
            public DataSet FillDataSet(List<T> modelList)
            {
                if (modelList == null || modelList.Count == 0)
                {
                    return null;
                }
                else
                {
                    DataSet ds = new DataSet();
                    ds.Tables.Add(FillDataTable(modelList));
                    return ds;
                }
            }

            /// <summary>
            /// 实体类转换成DataTable
            /// </summary>
            /// <param name="modelList">实体类列表</param>
            /// <returns></returns>
            public DataTable FillDataTable(List<T> modelList)
            {
                if (modelList == null || modelList.Count == 0)
                {
                    return null;
                }
                DataTable dt = CreateData(modelList[0]);

                foreach (T model in modelList)
                {
                    DataRow dataRow = dt.NewRow();
                    foreach (PropertyInfo propertyInfo in typeof(T).GetProperties())
                    {
                        dataRow[propertyInfo.Name] = propertyInfo.GetValue(model, null);
                    }
                    dt.Rows.Add(dataRow);
                }
                return dt;
            }

            /// <summary>
            /// 根据实体类得到表结构
            /// </summary>
            /// <param name="model">实体类</param>
            /// <returns></returns>
            private DataTable CreateData(T model)
            {
                DataTable dataTable = new DataTable(typeof(T).Name);
                foreach (PropertyInfo propertyInfo in typeof(T).GetProperties())
                {
                    dataTable.Columns.Add(new DataColumn(propertyInfo.Name, propertyInfo.PropertyType));
                }
                return dataTable;
            }

            #endregion
        }
    }
}
